Atherosclerosis is the accumulation of fatty material (consisting mainly of cholesterol, fibrous material and calcium) forming an atheroma or plaque beneath the endothelium of the artery.
Atherosclerosis is the root cause of various cardiovascular diseases (CVD) such as angina, heart attack, stroke and peripheral disease.
If the atheroma ruptures it can damage the endothelium of the artery. This damage leads to a cascade of events which leads to the formation of a blood clot.
damage to the endothelium releases clotting factors
clotting factors convert the enzyme prothrombin to thrombin
thrombin causes the plasma protein fibrinogen to form threads of fibrin
fibrin threads mesh together clotting the blood and sealing the wound
scar tissue forms on this scaffold creating a clot
If a thrombus breaks loose, it forms an embolus that travels in the bloodstream and may end up blocking a blood vessel completely.
If the embolus blocks a coronary artery it may lead to a heart attack (myocardial infarction) or can cause a stroke if it blocks an artery supplying the brain. In either case, tissue death can occur due to a lack of oxygen.
As the atheroma continues to build up it causes several things to happen:
the artery loses its elasticity
the blockage restricts blood flow due to the decreaseddiameter of the lumen
the restricted blood flow increases blood pressure
